Orthodontics is a specialty of dentistry that is concerned with the study and treatment of malocclusions (improper bites) which can be a result of tooth irregularity, disproportionate jaw relationships, or both. Orthodontic treatment can focus on dental displacement only and can be carried out for purely aesthetic reasons with regard to improving the general appearance of patient's teeth. However, there are other orthodontic treatments that are more complex and are needed to reconstruct the face. This type of treatment is most often prescribed for practical reasons such as providing the patient with a functionally improved bite (occlusion).
Conventionally, repositioning teeth for aesthetic reasons or other reasons is accomplished by wearing a device that is commonly referred as dental braces. Dental braces are formed of a variety of appliances such as brackets, archwires, ligatures, and O-rings. Attaching dental braces to the teeth of a patient is a tedious, time consuming task that requires a number of meetings between the patient and orthodontist to first prepare and fit the dental braces and then make necessary adjustments to the dental braces. Before the braces are fixedly attached to the patient's teeth, various molds and fittings are required in order to formulate the strategy. To attach the braces, a weak acid is first applied to the teeth to increase the adherence of the braces to the teeth. Brackets and bands that form the dental braces are bonded to the patient's teeth using cement.
The primary force-inducing appliance in a conventional set of braces is the archwire. The archwire is resilient and is attached to the brackets by way of slots in the brackets. The archwire links the brackets together and exerts forces on them to move the teeth over time. After the archwire is in place, periodic meetings with the orthodontist are required and during these meetings, the patient's braces are adjusted by installing a different archwire having different force-inducing properties or by replacing of tightening existing ligatures.
Besides being a time consuming process, conventional braces are also very unsightly and are uncomfortable to wear to the presence of these components in the mouth, bonded to and extending across the teeth, etc.
In recent years, improvements in the field of orthodontistry have produced dental products that are alternatives to conventional braces. For example, a dental system available under the name “Invisalign®” is distributed by Align Technologies. This system involves a process where, once a candidate is found to be suitable for wearing this type of product, impressions and pictures of the patient's teeth are taken. The teeth impressions are digitized and sent to the company to establish a plan for tooth movement over a treatment timeline which is typically 18 months. Based on a precise treatment plan, customized aligners are created for the patient to wear at each stage of the treatment. Typically, a full set of treatment includes 20-30 aligners per arch. The aligners are worn as much as possible, with the exception of eating and drinking, in order to complete the treatment within the timeline established with the patient.
The Invisalign® system is a computer based system in which not only are the imprints digitized and stored in memory but also the computer uses algorithms and the like to develop virtual correction steps (i.e., incremental changes in the teeth to be implemented over months or years). After the virtual correction steps are calculated, a sophisticated laser machining of multiple adjusters controlled by the same computer. Therefore, the production is expensive and a complete set of braces is made in advance and corrective interaction during the treatment process is practically not feasible.
The Invisalign® system is fairly costly to patients and also the plan is designed to be implemented over a long time period. As a result, the patients typically wear a particular aligner for a single month and due to the substantial number of aligners that are used, the process is implemented over a substantial number of months. For example, the patient is given a tray of about 20 aligners which are used by the patient over the next 20 successive months.
Due to certain limitations of the Invisalign® system, some of which are described herein, the course of treatment is spread out over many months as a result of the slight incremental changes that are incorporated into the aligners. For example, the Invisalign® system uses a laser incorporated as part of a vacuum forming machine that is used to heat and thereby form the aligner and, therefore, the thickness of the vacuum forming material is limited to thicknesses that can be processed with the laser without destroying the material. This imposes a limitation on the manufacturing process as well as the treatment time table that can be proposed to a patient.
While the Invisalign® system has merit, it would be advantageous to provide a system that is model that has a plurality of tooth dies is provided.